Electro-mechanical transducer



73- 1 mus: nuum Dec. 29, 1964 w. DICKINSON 3,163,786

ELECTRO-MECHANICAL TRANSDUCER 1; Filed May 15. 1961 STRANDED CONDUCTORS 1 INVENTOR.

MLL/AM 0/c/r/rvscw L L] BY fl/ZM \I3 I AGQ'NT' GR I 310/27 United States Patent Ofiiice a ented Dec. 29, 1964 ,.?z.l r ELECTROHVIECHANICAL TRANSDUCER William Dickinson, Los Angeles, Calif., assignor t McCullough and Associates, Culver City, Los Angeles, Calif., a partnership Filed May 15, 1961, Ser. No. 119,765 8 Claims. (Cl. 310-27) This invention relates to a lineal motion transducer and is particularly concerned with an electro-mechanical transducer for vibratory testing, and the like, it being a general object of this invention to provide an electromechanical structure wherein moving mass is reduced to a minimum and wherein a high degree of mechanical and electrical efiiciency is attained.

Machines of the type under consideration have had certain limitations of design which has resulted in restricted use. Mainly, the armatures of such machines have been heavy and bulky with the result that the over all construction has been inefiicient. Since the armature is a reciprocating element, its weight is an important factor requiring power for its operation or reciprocation. That is, the heavier the armature, the less capacity it will have to carry a component to be tested. It is, therefore, a primary object of this invention to provide a light weight armature in a machine of the type under consideration so that the carrying power of the machine is increased to a maximum degree. Such a construction also results in a lower power consumption and in more accurate response to line signals.

Heretofore, electro-mechanical transducers have been characterized by circular armature coils and by external and internal field poles with magnetic flux extending across an annular air gap occupied by the said armature coil. More recently, however, radical departure from the circular configuration has been suggested and tried with a degree of success but great sacrifices in the electrical efficiency. For example, X-shaped armatures have been resorted to wherein the structural X per se forms the armature conductors, and in such a machine extremely high amperage must be employed accompanied by high losses, etc. In theory, it is the large cross-section of the armature conductors in such an arrangement that requires the high current requirements. On the contrary, the present invention employs relatively low current and relatively small cross-sectioned armature conductors accompanied by low losses. The present invention retains the long proven concept of a multi-turn armature coil, attaching said coil to a useful load by means of a minimum of structure. The useful load in the case under consideration is a component (not shown) to be reciprocated, the armature being formed into or onto a light weight carriage that is attached to the said useful load.

It is an object of this invention to provide a versatile lineal transducer having a rectilinear or reciprocating motion and with a minimum of built-in mass inertia. With the structure that I provide the armature structure is no more than a single fiat web with a rail for facilitating attachment to the load.

It is another object of this invention to provide a configuration and combination of parts and elements wherein the coils, both field and armature coils, can be preformed and simply installed in the structure upon assembly and/or for replacement.

The various objects and features of this invention will be fully understood from the following detailed description of the typical preferred form and application thereof, throughout which description reference is made to the accompanying drawings, -in which:

FIG. 1 is a section view taken through the transducer in perspective.

FIG. 2 is an enlarged detailed section of a portion of the structure shown in FIG. 1.

FIG. 3 is a fragmentary perspective view of one convolution or coil of the armature winding that I provide.

FIG. 4 is a plan view of the field-frame that characterizes the transducer shown in FIG. 1.

The lineal transducer or shaker of the present invention is driven electrically and operates on alternating current. The frequency and power of the current is varied as circumstances require in order to gain the desired frequency and intensity of vibration, and for this purpose, any suitable electronic power supply may be provided. It will be readily understood that the fre quency of vibration in the machine will follow the frequency of the alternating current and that the intensity or stroke of the vibration in the machine will follow the power input or voltage and amperage which is supplied. Further, it will be apparent that impacts can be created by applying a single .pulse of DC. electricity, or long stroke acceleration can be created in a like manner.

The shaker that I illustrate in the drawings is a unit of construction adapted to carry and vibrate a load'su'ch' as a unit of machinery or of electronic equipment that requires observation under predetermined vibratory conditions. As shown, the unit of construction comprising the present invention involves, generally, a field-frame F and an armature-carriage A. The field-frame F is the stationary element, whereas the armature-carriage A is the moving element.

The field-frame F is a rigid structure adapted to be fixedly positioned, or of substantial weight so that its inertia has considerable effect. The field-frame F can be made to have a simple pair of magnetic poles, N and S, or it can be multi-poled having as many pairs of poles as circumstances may require. In the drawings I have shown three pairs of poles, N and S, and with three armature windings W each operating between opposing field poles. It will be apparent that the present invention in its broad sense contemplates the combination of a single armature winding W and a single pair of field poles N and S, and that the direction of reciprocatory movement is in opposite directions longitudinally of the field pole structure as is indicated by the arrow (1.

The field-frame F involves, at least, a pair of elongate magnets 10 and 20 having opposed pole faces 11 and 21, respectively. The faces 11 and 21 are spaced to accommodate the intervening armature-carriage parts later described, and said faces are of limited transverse extent, or width. As shown, the faces 11 and 21 are straight and parallel and of uniform width. The magnets 10 and 20 are alike, being formed as rigid bars anchored at one or both ends. In the preferred arrangement, the magnets 10 and 20 are electromagnets comprising a solid body of, or laminated, electrical steel anchored at opposite ends to rails 12 and 13 and with a field winding 14 to create the necessary mangetic flux to cross between the faces 11 and 21. Further, when multiple pairs of magnets are employed the intermediate magnets 10 and 20 are combined in one solid body, or lamination, each having oppositely disposed faces 11 and 21. Thus, it will be apparent that as many pairs of magnets can be employed as is desired.

The armature-carriage A is a rigid structure adapted to be reciprocably moved relative to the field-frame F, and it is of minimum weight and inertia. The armaturecarriage A is essentially little more than the winding W of which it is mainly composed, said winding W being attached together in a common body 30 that is essentially the carriage to which the work load is attached. More specifically, portions of the multi-coiled conductor 31 of the winding W are cast or molded in the body 30 to extend through the air gap at a right angle to the longitudinal 3X68 f the g -mnot the riage, thus avoiding the use of flexible loops and stationary polar axes). In accordance with the invention, the winding portions. With this latter induction concept of 30 is dielectric and is co-extensive with the pole face 11, ding the armature, unlimited travel can be gained by the conductor 31 being imbedded therein so that adopertifingihe armature between a long series of field elejacent coil portions are insulated from each other. As merits. H shown, there is a single layer of conductor 31 to be re- From the foregoing, iiTvill be napparenLjhat I have ciprocated between the pole faces 11 and 21, and the body provided a relatively simple field and armatureconstruc- 30 is but slightly greater in thickness than the cross-section that can be readily manufactured of easily formed and tion of a single conductor, and said conductors are spaced easily assembled parts. The armature-carriage elementv A slightly to extend one adjacent the other. that is shown is made somewhat shorter in longitudinal In carrying out the preferred form of this invention, extent than the field-frame element F in order to permit We thewindingjy is also attachgi together in a common body the desired longitudinal reciprocatory movement. The

40 that is fixedTotheafield-frame RQ lore specifically, armature-carriage can be supported in various ways and, portions of the multi-coiled conductor 31 of't ing for example, it can be carried by an anti-friction fluid W are cast or molded in the body 40 to extend transversely 1D rt, in which case the frame provides a closed chamthrough the air gap at a right angle to the longitudinal axes ber 55 suppl'idvvithtfiuid under pressure through fluid of the magnets 10 and (not the polar axes). In acgalleries 56. The said galleries discharge fluid in a mancordance with the invention, the body 40 is dielectric and ner to flat the armature-carriage in proper working posiis co-extensive with the pole face 11 or 21, as the case tion. Further, the fluid that is introduced for support of may be, the conductor portions 31 being imbedded therein 20 the carriage is also effective in heat transfer from the unit so that adjacent coil portions are insulated from each a it is operating.

other. As shown, there is a single layer of conductor por- Having de cribed only a typical preferred form and tions 31 to be superimposed upon the face 11 or 21, in application of my invention, I do not wish to be limited which case he y 4 i ligh ly gr r in hickness or restricted to the specific details herein set forth, but vthan the CIOSS-SeCiiOII 0f 8 Single Conductor and h C lwish to reserve to myself any modifications or variations ductors are Spaced g y to mend one adjacent the that may appear to those skilled in the art and fall within Otherthe scope of the following claims.

The winding W can be a single coil comprising one or Having described my invention, I claim:

more conductors 31 and in the pre ed o m o t 1. An electro-mechanical transducer including, a field invention, the said conductor 31, or conductors, is of the magnet comprising spaced pole faces, an armature commulti-strand type in order to have considerable flexibility. prising a winding having a fixed portion and a recipro- As shown, each coil of the conductor 31 has a pair of cable portion, said two portions being joined by flexible opposite loops 33 and 34 that extend freely intermediate 100p portions, the fixed portion of the winding being the bodies 30 and 40, and th s l ps 33 nd 4 p rmit positioned between the pole faces, and the reciprocable freedom for the y 30 to move independently of the 35 portion of the winding being secured to a body for free fixed body 40. reciprocatory movement.

The bodies 30 and ar Casi or m ld 80 as to 2. An electromechanical transducer including, a field encase the portions of the winding W, as above described, magnet comprising spaced pole faces, an armature com and said bodies are secured in place with the body or prising a winding having a fixed portion and a reciprobodies 30 movable, and the body or bodies 40 fixed to the 40 cable portion, said two portions being joined by flexible pole faces 11 and 21. The manner of securement can be loop portions, the fixed portion of the winding being varied, it being preferred to bond the bodies 40 to the fixed to at least one of the pole faces, and the reciprofaces 11 and 21 by means of a cement or adhesive. Furcable portion of the winding being secured to a body for Iher, since there are opposed pole faces 11 and 21 there free reciprocatory movement. are actually two windings W which are combined as 3. An electro-mechanical transducer including, a field one, or preferably secured together by joining the two magnet comprising spaced pole faces, an armature combodies 30 that are involved. The two bodies 30 are prising a winding having a fixed portion and a reciproeither cast or molded integrally as one, or they are cable portion, said two portions being joined by flexible bonded together by means of a cement or adhesive. loop portions, the fixed portion of the winding being As stated, the armature-carriage A is provided to move fixed to at least one of the pole faces, and the reciproa useful load to which it must be attached. Therecable portion of the winding being encased in a body fore, I prefer to secure the movable bodies 30 to a carfor free reciprocatory movement. riage to have supporting and driving engagement with 4. An electro-mechanical transducer including, a field a load. In practice, the carriage 50 comprises a web 51, magnet comprising spaced pole faces, an armature compreferably of metal such as aluminum, that extends in a prising windings having a pair of fixed portions and a plane intermediate the faces 11 and 21 and between the reciprocable portion, said fixed and reciprocable portwo bodies 30. The said bodies 30 carrying the armature tions being joined by flexible loop portions, the fixed porconductor 31 are then cast or molded onto or bonded to .1 tions of the windings being fixed to the pole faces, and the web 51. The web can be relatively thin and it supthe reciprocable portions of the windings being secured ports a rail 52 with fastener openings 53 for mounting to a body for free reciprocatory movement. engagement with the load. In practice, when a multi- 5. An electro-rnechanical transducer including, a field magnet unit is constructed as shown, a mounting plate magnet comprising spaced pole faces, an armature com- 55 joins the rails 52 properly spacing them, one parallel prising windings having a'pair of fixed portions and a with the other. reciprocable portion, said fixed and reciprocable portions In the preferred form of the invention illustrated and being joined by flexible loop portions, the fixed portions hereinabove described the armature winding involves porof the windings being encased in bodies that are fixed tions that are stationary and portions that move. Broadly, to the pole faces, and the reciprocable portions of the these armature windings can be varied in physical formawindings being secured to a body for free reciprocatory tion as circumstances require. For example, the moving movement. portions of the windings can be formed of laminations that 6. An electro-mechanical transducer including, a field form the body of the armature-carriage, in which case magnet comprising spaced pole faces, an armature comflexible loops extend freely to a stationary portion or prising windings having a pair of fixed portions and a Portions as above described- Also, for p inducreciprocable portion, said fixed and reciprocable portions tion can be utilized in'the armature windings, in which being joined by flexible loop portions, the fixed portions case the entire winding can move with the armature carof the windings being fixed to the pole faces, and the reciprocable portions of the windings being encased in a body for free reciprocatory movement.

7. An electro-mechanical transducer including, a field magnet comprising spaced pole faces, an armature comprising windings having a pair of fixed portions and a reciprocable portion, said fixed and reciprocable portions being joined by flexible loop portions, the fixed portions of the windings being encased in bodies that are positioned between the pole faces, and the reciprocable portions of the windings being encased in a body for free reciprocatory movement.

8. An electro-mechanical transducer including, a field magnet comprising spaced pole faces, an armature comprising windings having a pair of fixed portions and a reciprocable portion, said fixed and reciprocable portions 6 being joined by flexible loop portions, the fixed portions of the windings being encased in bodies that are fixed to the pole faces, and the reciprocable portions of the windings being encased in a body for free reciprocatory movement.

References Cited in the file of this patent UNITED STATES PATENTS 

1. AN ELECTRO-MECHANICAL TRANSDUCER INCLUDING, A FIELD MAGNET COMPRISING SPACED POLE FACES, AN ARMATURE COMPRISING A WINDING HAVING A FIXED PORTION AND A RECIPROCABLE PORTION, SAID TWO PORTIONS BEING JOINED BY FLEXIBLE LOOP PORTIONS, THE FIXED PORTION OF THE WINDING BEING POSITIONED BETWEEN THE POLE FACES, AND THE RECIPROCABLE PORTION OF THE WINDING BEING SECURED TO A BODY FOR FREE RECIPROCATORY MOVEMENT. 